Internal control systems of evaporator and condenser fan motor assemblies of a refrigeration system in a refrigerator unit

ABSTRACT

A refrigeration system for use in a refrigerator unit, the refrigeration system including a compressor having an ON state and an OFF state, a condenser, a temperature sensor, an evaporator, and an evaporator fan motor assembly. The evaporator fan motor assembly has an evaporator fan motor, a fan blade, and an internal control system. The internal control system of the evaporator fan motor assembly is adapted to sense the compressor state and is further adapted to operate the evaporator fan motor in response to the sensed compressor state. The refrigeration system may further include a condenser fan motor assembly. The condenser fan motor assembly has a condenser fan motor, a fan blade, and an internal control system. The internal control system of the condenser fan motor is adapted to sense the compressor state and is further adapted to operate the condenser fan motor in response to the sensed compressor state.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent App. No.61/952,294, filed on Mar. 13, 2014, the contents of which areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to refrigerator units and, moreparticularly, to refrigerator units that comprise a refrigeration systemwith an evaporator fan motor assembly having an internal control systemand/or a condenser fan motor assembly having an internal control systemwherein the evaporator fan motor and/or the condenser fan motor can beoperated intermittently for assisting in reducing energy consumption.

BACKGROUND

The principal components of a typical refrigerator unit, such as thoseused in residential, commercial and industrial applications, include astorage compartment which is refrigerated by a refrigeration system andis used to store and/or display various food products at lowtemperatures. The refrigeration systems of typical refrigerator unitsinclude a refrigerant flowing serially through a compressor, acondenser, a thermal expansion valve or capillary tube, and anevaporator. Additionally a condenser fan motor assembly is used to blowair across the coils of the condenser. An evaporator (cold air) fanmotor assembly is used to blow air across the evaporator. In thesetypical refrigerator units the condenser fan motor runs while thecompressor operates (i.e., the compressor ON state). The compressortypically cycles on and off about three times an hour. Additionally, theevaporator fan motor runs both during the compressor ON state and duringthe compressor OFF state.

The constant running of the evaporator fan motor assists in providinguniform product temperature throughout the interior volume of thestorage compartment regardless of the relationship of the ON-OFF stateof the compressor ((whether the compressor cycles from the ON state tothe OFF state frequently (e.g., more than 6 cycles per hour) orinfrequently (e.g., once or twice an hour)). Under some circumstances,the evaporator fan motor can be powered off when the compressor ispowered off. This is typically done for energy saving reasons. If theactual compressor run time (i.e., the ratio of on time to real time) isvery low because of low ambient temperature or general sizing of therefrigeration system to the volume of the storage compartment, this canlead to instability of the product temperature inside the storagecompartment. The product temperature may begin to swing up and down withthe compressor cycles, thereby adversely affecting the integrity of thefood products stored within the storage compartment. Accordingly,turning off the evaporator fan motor during the compressor OFF state cansave energy, but can have a negative effect on the food product.

In prior art refrigerator units, the condenser fan motor runs while thecompressor operates (i.e., the compressor ON state) and the evaporatorfan motor runs both during the compressor ON state and during thecompressor OFF state. The constant running of the evaporator fan motorassists in providing uniform product temperature throughout the interiorvolume of the storage compartment, however the constant running of theevaporator fan motor also increases the energy consumption of therefrigerator unit. In certain other prior art refrigerator units, anexternal control system may be employed which may be adapted to controlthe compressor, condenser fan and/or evaporator fan motor. The controlsystem may be connected to an electronic thermostat and can control eachof the refrigeration components based on the temperature sensed by theelectronic thermostat. This external control system may be disposed onor in the refrigerator unit. Such an external control system, includingthe electronic thermostat, may be expensive to design and implement.Additionally, the external control system may need to be tailored tovarious types and/or sizes of refrigerator units.

SUMMARY OF THE INVENTION

Briefly, therefore, one embodiment of the invention is directed to arefrigeration system in which the condenser fan motor and/or theevaporator fan motor may be operated by control systems internal to eachof the condenser fan motor assembly and/or the evaporator fan motorassembly for reduced energy consumption while maintaining uniformproduct temperature in the storage compartment.

Another embodiment of the invention is directed to a refrigerationsystem for use in a refrigerator unit, the refrigeration systemcomprising a compressor having an ON state and an OFF state, acondenser, a thermostat, an evaporator, and an evaporator fan motorassembly comprising an evaporator fan motor, a fan blade, and aninternal control system, wherein the internal control system is adaptedto sense the compressor state and is further adapted to operate theevaporator fan motor in response to the sensed compressor state.

Another embodiment of the invention is directed to a method of operatinga refrigeration system for use in a refrigerator unit, wherein therefrigeration system comprises a compressor having an ON state and anOFF state, a condenser, a thermostat, an evaporator, and an evaporatorfan motor assembly comprising an evaporator fan motor, a fan blade, andan internal control system, wherein the internal control system isadapted to repeatedly cycle the evaporator fan motor between an ON stateand an OFF state when the compressor is in the OFF state. The methodcomprises the steps of: turning the compressor to the ON state; sensingby the internal control system of the evaporator fan motor assembly thatthe compressor is in the ON state and turning the evaporator fan motorto the ON state; turning the compressor to the OFF state; sensing by theinternal control system of the evaporator fan motor assembly that thecompressor is in the OFF state and repeatedly cycling the evaporator fanmotor between the ON state and the OFF state.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects and advantages of the invention willbecome more fully apparent from the following detailed description,appended claims, and accompanying drawings, wherein the drawingsillustrate features in accordance with exemplary embodiments of theinvention, and wherein:

FIG. 1 is a right perspective view of a refrigerator unit according toan embodiment of the invention;

FIG. 2 is a schematic drawing of a refrigeration system of arefrigerator unit according to an embodiment of the invention;

FIG. 3 is a wiring diagram of components of a refrigeration system of arefrigerator unit according to an embodiment of the invention;

FIG. 4 is a flowchart of a method of operation of a refrigeration systemof refrigerator unit having an evaporator fan motor assembly with aninternal control system according to an embodiment of the invention;

FIG. 5 is a flowchart of a method of operation of a refrigeration systemof a refrigerator unit having a condenser fan motor assembly with aninternal control system according to an embodiment of the invention;

FIG. 6 is a flowchart of a method of operation of a refrigeration systemof a refrigerator unit having an evaporator fan motor assembly with aninternal control system and a condenser fan motor assembly with aninternal control system according to an embodiment of the invention;

FIG. 7 is a time plot of a method of operation of a refrigeration systemof a refrigerator unit having an evaporator fan motor assembly with aninternal control system and a condenser fan motor assembly with aninternal control system according to an embodiment of the invention; and

FIG. 7A is a time plot of a method of operation of a refrigerationsystem of a refrigerator unit having an evaporator fan motor assemblywith an internal control system and a condenser fan motor assembly withan internal control system according to an embodiment of the invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it willbe understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it will be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. All numbers expressing measurements and soforth used in the specification and claims are to be understood as beingmodified in all instances by the term “about.” It should also be notedthat any references herein to front and back, right and left, top andbottom and upper and lower are intended for convenience of description,not to limit an invention disclosed herein or its components to any onepositional or spatial orientation.

As illustrated in FIG. 1, one embodiment of the invention is arefrigerator unit 10 having a refrigeration system disposed withinrefrigerator unit 10. In certain embodiments, for example, refrigeratorunit 10 may be a glass door merchandiser which may be used to store anddisplay products such as food and/or drinks for sale. However, it willbe understood that refrigerator unit 10 may be any type of refrigerationunit, including, but not limited to, residential, commercial and/orindustrial refrigerators, vending machines, and freezers. Refrigeratorunit 10 may include a lower portion providing a refrigeration systemhousing 12 and an upper portion providing a cabinet 14. Some or all ofcomponents of refrigeration system 110 (see FIG. 2) may be disposedwithin refrigeration system housing 12. As shown, cabinet 14 includes atop 16, a bottom 18, opposed sides 20 and a back 22 defining a storagecompartment 24 having an opening 26. Opening 26, in the embodimentshown, may be closed by a pair of doors 28 which may be substantiallyidentical, each door 28 being attached to one of said cabinet sides 20in swinging relation to said opening 26. While certain embodimentsinclude a pair of doors 28, it will be understood by one of ordinaryskill in the art that any number of doors may be used without departingfrom the scope of the invention.

FIG. 2 illustrates certain principal components of one embodiment of arefrigeration system 110 for use in a refrigerator unit 10.Refrigeration system 110 may include a compressor 112, a condenser 114for condensing compressed refrigerant vapor discharged from thecompressor 112, a thermal expansion device 118 for lowering thetemperature and pressure of the refrigerant, an evaporator 120, and athermostat or temperature control 130. Thermostat 130 may be adapted tocontrol the operation of refrigeration system 110 in response to thetemperatures measured within storage compartment 24. Accordingly,compressor 112 may have an ON state (“ON”) and an OFF state (“OFF”)wherein thermostat 130 causes compressor 112 to turn ON or OFF based onthe temperature within storage compartment 24. Thermostat 130 may be amechanical or electrical thermostat or temperature control. In variousembodiments, thermostat 130 may include a relay and capillary tube formeasuring the temperature within storage compartment 24 and forcontrolling compressor 112. The thermal expansion device 118 mayinclude, but is not limited to, a capillary tube, a thermostaticexpansion valve or an electronic expansion valve. In certainembodiments, where thermal expansion device 118 is a thermostaticexpansion valve or an electronic expansion valve, refrigeration system110 may also include a temperature sensing bulb (not shown) placed atthe outlet of the evaporator 120 to control thermal expansion device118. As described more fully elsewhere herein, a form of refrigerantcycles through these components via a lines 128 a, 128 b, 128 c.

Refrigeration system 110 may further include a condenser fan motorassembly 115 which may be positioned to blow a gaseous cooling medium(e.g., air) across condenser 114. Condenser fan motor assembly 115 mayinclude a fan motor 115 a, fan blade(s) 115 b and an internal controlsystem (not shown) adapted to control the operation of condenser fanmotor 115 a. Condenser fan motor 115 a may be connected to fan blade(s)115 b in any manner known in the art to cause fan blade(s) 115 b torotate and thus move air. The internal control system of condenser fanmotor assembly 115 may be adapted to sense the ON or OFF state ofcompressor 112 and may be further adapted to operate condenser fan motor115 a in response to the sensed compressor 112 state (e.g., the ON stateor the OFF state).

Additionally, refrigeration system 110 may further include an evaporatorfan motor assembly 127 which may be positioned to blow air acrossevaporator 120 in order to circulate cooled air within refrigerator unit10. Evaporator fan motor assembly 127 may include a fan motor 127 a, fanblade(s) 127 b and an internal control system (not shown) adapted tocontrol the operation of evaporator fan motor 127 a. Evaporator fanmotor 127 a may be connected to fan blade(s) 127 b in any manner knownin the art to cause fan blade(s) 127 b to rotate and thus move air. Theinternal control system of evaporator fan motor assembly 127 may beadapted to sense the ON or OFF state of compressor 112 and may befurther adapted to operate evaporator fan motor 127 a in response to thesensed compressor 112 state (e.g., the ON state or the OFF state).

The internal control systems in each of evaporator fan motor assembly127 and condenser fan motor assembly 115 may assist in reducing energyconsumption while keeping costs low. The internal control systems mayoperate evaporator fan motor 127 a and condenser fan motor 115 a withoutrequiring additional, expensive, electronic temperature controls withspecific relays for this purpose. Preferably, evaporator fan motorassembly 127 includes an internal control system and condenser fan motorassembly 115 includes an internal control system. The internal controlsystem of evaporator fan motor assembly 127 may be independent of theinternal control system of condenser fan motor assembly 115.Accordingly, the internal control systems of evaporator fan motorassembly 127 and/or condenser fan motor assembly 115 do not need tocommunicate with one another and/or do not need to rely on one anotherin order to control evaporator fan motor 127 a and/or condenser fanmotor 115 b.

In various embodiments, fan motors 127 a, 115 a of evaporator fan motorassembly 127 and condenser fan motor assembly 115, respectively, may beelectronically commutated motor(s) (ECMs) that have an internal circuitboard modified for the purpose of sensing the compressor line voltage,an in-line circuit, and/or other electric or electronic components(i.e., integrated circuits, microprocessors, memory, etc.) designed forcycling evaporator fan motor 127 a and/or condenser fan motor 115 abetween an OFF state (“OFF”) and an ON state (“ON”) until compressor 112is turned ON again by thermostat 130. For example, in certainembodiments, evaporator fan motor 127 a and/or condenser fan motor 115 acan be repeatedly cycled OFF for 5 minutes and then ON for 1 minute.Typical internal ECM motor electronics do not have enough internal boardlevel isolation to properly sense the compressor line voltage, thuscondenser fan motor assembly 115 and evaporator fan motor assembly 127may each incorporate circuit board design and components not found intypical condenser and evaporator fan motor assemblies in order toachieve the board level isolation required for correctly operatingcondenser fan motor 115 a and evaporator fan motor 127 a.

Referring now to FIG. 3 a wiring diagram of an embodiment ofrefrigeration system 110 is illustrated. Evaporator fan motor assembly127 may be electrically connected to line 134 and neutral wire 136 viapower supply wire 137 and neutral wire 138, respectively. Additionally,thermostat 130 may be electrically connected to line 134. Condenser fanmotor assembly 115 and compressor 112 may be wired in parallel betweenthermostat 130 and neutral wire 136. As stated above, in variousembodiments, thermostat 130 may include a relay and capillary tube formeasuring the temperature within storage compartment 24. When thetemperature within storage compartment 24 rises above the desired settemperature, the relay of thermostat 130 closes thereby completing thecircuit and tuning ON compressor 112. A digital control input wire 132may be connected to the live output side of thermostat 130 and maypermit internal control system of evaporator fan motor assembly 115 tosense a line voltage in the circuit when the relay of thermostat 130closes.

The internal control system of condenser fan motor assembly 115 may notrequire a separate digital control input wire to determine line voltagebecause the internal control system can sense the line voltage incondenser power line 140 when the relay of thermostat 130 closes. Theinternal control systems of each of condenser fan motor assembly 115 andevaporator fan motor assembly 127 permit the use of a simple, cheap andreliable mechanical thermostat 130. Accordingly, condenser fan motorassemblies 115 and/or evaporator fan motor assemblies 127 with internalcontrol systems may be placed into existing refrigerator units withoutthe need for costly external control systems. Thus, existingrefrigerator units can be retrofitted with condenser fan motorassemblies 115 and/or evaporator fan motor assemblies 127 havinginternal control systems and energy efficiency gains may be realizedwith a low cost.

Preliminary testing to date has indicated an estimated energy savings ona typical 115 volt model (two solid door upright refrigerator) ofbetween 15 and 25 percent over current production construction. Thesenumbers may vary based on the volume of storage compartment 24 and theratio of the size of refrigeration system 110 to the volume of storagecompartment 24. For example, in certain embodiments, larger amounts ofenergy savings may be realized with refrigeration systems 10 that aremore lightly loaded (i.e., where compressor 112 is designed to be OFFfor longer periods of time).

Having described each of the individual components of one embodiment ofrefrigeration system 110, the manner in which the components interactand operate in various embodiments may now be described in referenceagain to FIG. 2. During operation of refrigeration system 110,compressor 112 receives low-pressure, substantially gaseous refrigerantfrom evaporator 120 through suction line 128 c, pressurizes therefrigerant, and discharges high-pressure, substantially gaseousrefrigerant through discharge line 128 a to condenser 114. In condenser114, heat is removed from the refrigerant, causing the substantiallygaseous refrigerant to condense into a substantially liquid refrigerant.

After exiting condenser 114, the high-pressure, substantially liquidrefrigerant is routed through liquid line 128 b to thermal expansiondevice 118 (e.g., a capillary tube, a thermostatic expansion valve, anelectronic expansion valve, etc.), which reduces the pressure of thesubstantially liquid refrigerant for introduction into evaporator 120.As the low-pressure expanded refrigerant is passed through tubing ofevaporator 120, the refrigerant absorbs heat from the tubes containedwithin evaporator 120 and vaporizes as the refrigerant passes throughthe tubes. This cools evaporator 120 and evaporator fan motor assembly127 blows air over or through the coils (not shown) of evaporator 120 inorder to circulate cooled air within refrigerator unit 10. Low-pressure,substantially gaseous refrigerant is discharged from the outlet ofevaporator 120 through suction line 128 c, and is reintroduced into theinlet of compressor 112.

Operation of Evaporator Fan Motor Assembly

In certain embodiments, refrigeration system 110 of refrigerator unit 10may include an evaporator fan motor assembly 127 having an internalcontrol system for repeatedly cycling evaporator fan motor 127 a betweenan ON state (“ON”) and an OFF state (“OFF”). This cycling can beintermittent (i.e., the OFF time and the ON time do not need to beequal). As stated above, evaporator fan motor assembly 127 may include afan motor 127 a, fan blade(s) 127 b, and an internal control system (notshown) adapted to control the operation of evaporator fan motor 127 a.The internal control system of evaporator fan motor assembly 127 may beadapted to sense the compressor line voltage via digital control inputwire 132 (see FIG. 3) such that the internal control system may be ableto sense when compressor 112 is turned ON or OFF by thermostat 130.Accordingly, the internal control system may control evaporator fanmotor 127 a without the need for an external and/or additional controlsystem.

Referring now to FIG. 4, one embodiment of internal control ofevaporator fan motor assembly 127 is described in detail. At step 300,compressor 112 is turned ON by thermostat 130. At step 302, the internalcontrol system of evaporator fan motor assembly 127 senses thatcompressor 112 has turned ON and turns ON evaporator fan motor 127 acausing fan blade(s) 127 b to rotate and blow air across evaporator 120.Accordingly, evaporator fan motor 127 a can operate continuously whilecompressor 112 is ON. At step 304, compressor 112 is turned OFF bythermostat 130. In certain embodiments, during optional steps 306, 308and 310, while compressor 112 remains OFF and for a second time intervalafter compressor 112 has turned OFF, evaporator fan motor 127 a mayremain ON. By continuing to operate evaporator fan motor 127 a for aperiod of time after compressor 112 turns OFF, cooling of storagecompartment 24 may continue because residual cool refrigerant remains inevaporator 120 even after compressor 112 stops running.

The internal control system of condenser fan motor assembly 127 mayinclude a timer for measuring elapsed time. The timer may be reset eachtime compressor 112 turns ON. In certain embodiments, the internalcontrol system of evaporator fan motor assembly 127 may include aprocessor which may provide a timing function. The timer may beimplemented via hardware, software, and/or firmware within the internalcontrol system of evaporator fan motor assembly 127 in any manner knownin the art without departing from the scope of the invention. When thesecond time interval has elapsed, at step 308, the internal controlsystem of evaporator fan motor assembly 127 turns OFF evaporator fanmotor 127 a at step 312. In certain embodiments where optional steps306, 308 and 310 are not performed, when compressor 112 is turned OFF atstep 304, internal control system of evaporator fan motor assembly 127turns OFF evaporator fan motor 127 a at step 312. Accordingly, incertain embodiments, evaporator fan motor 127 a may not continue toremain ON for a second time interval.

Then at step 314, the internal control system of evaporator fan motorassembly 127 monitors whether compressor 112 has turned ON. As long ascompressor 112 remains OFF, evaporator fan motor 127 a may repeatedlycycle ON and OFF, thereby taking advantage of the energy savings byturning OFF evaporator fan motor 127 a for a period of time. However,the temperature in storage compartment 24 may be maintained by turningON evaporator fan motor 127 a for a period of time. Therefore, whilecompressor 112 is OFF, the internal control system of evaporator fanmotor assembly 127 keeps evaporator fan motor 127 a OFF during a thirdtime interval at step 316. When the third time interval has elapsed, theinternal control system of evaporator fan motor assembly 127 turns ONevaporator fan motor 127 a at step 318 causing fan blade(s) 127 b torotate and blow air across evaporator 120. Then at step 320, theinternal control system of evaporator fan motor assembly 127 monitorswhether compressor 112 has turned ON. As long as compressor 112 remainsOFF, the internal control system of evaporator fan motor assembly 127keeps evaporator fan motor 127 a ON during a fourth time interval atstep 324.

When the fourth time interval has elapsed, at step 322, the internalcontrol system of evaporator fan motor assembly 127 turns OFF evaporatorfan motor 127 a and the process returns to step 312. This process maythen repeat wherein the internal control system of the evaporator fanmotor assembly 127 repeatedly cycles evaporator fan motor 127 a ON andOFF while compressor 112 is OFF. By running evaporator fan motor 127 aduring repeated fourth time intervals, air will still be circulatedacross evaporator 120 by fan blade(s) 127 b to maintain the temperaturein storage compartment 24. Additionally, by keeping evaporator fan motor127 a OFF during repeated third time intervals, the heat generated byevaporator fan motor assembly 127 may be reduced, thereby reducing heattransfer from evaporator fan motor assembly 127 into storage compartment24. In certain embodiments, the amount of air required to maintain auniform temperature in storage compartment 24 during the compressor 112OFF state may be reduced by as much as a factor of ten (10) as comparedto the compressor 112 ON state.

As shown at steps 306 (optional step), 314, and 320, if compressor 112turns ON at any point, the cycle will be restarted at step 302 andevaporator fan motor 127 a will be turned ON or will remain ON.Accordingly, the compressor 112 ON state may interrupt the intermittentoperation of evaporator fan motor assembly 127 at any time.

The second, third and fourth intervals of time as described inconnection with steps 308 (optional step), 316, and 322 may be anylength of time and may vary according to a variety of design and/oroperating parameters including, but not limited to, storage compartment24 volume, ambient temperatures, storage compartment 24 operatingtemperature, etc. In certain embodiments, for example, the secondinterval of time, as described at step 308, may be about zero seconds toabout 1 minute (e.g., about zero seconds, about 5 seconds, about 10seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50seconds, about 55 seconds, about 60 seconds). In certain embodiments,for example, the third interval of time, as described at step 316, maybe about 1 minute to about 7 minutes (e.g., about 1 minute, about 2minutes, about 3 minutes, about 4 minutes, about 5 minutes, about 6minutes, about 7 minutes). In certain embodiments, for example, thefourth interval of time, as described at step 322, may be about 15seconds to about 2 minutes (e.g., about 15 seconds, about 30 seconds,about 45 seconds, about 60 seconds, about 1 minute and 15 seconds, about1 minute and 30 seconds, about 1 minute and 45 seconds, about 2minutes).

Operation of Condenser Fan Motor Assembly

In certain embodiments, refrigeration system 110 of refrigerator unit 10may additionally or alternatively include a condenser fan motor assembly115 having an internal control system independent from the internalcontrol system of evaporator fan motor assembly 127. As stated above,condenser fan motor assembly 115 may include a fan motor 115 a, fanblade(s) 115 b, and an internal control system (not shown) adapted tocontrol the operation of condenser fan motor 115 a. The internal controlsystem may be adapted to sense the compressor line voltage, such thatthe internal control system of condenser fan motor assembly 115 may beable to sense when compressor 112 is turned ON or OFF by thermostat 130.Accordingly, the internal control system of condenser fan motor assembly115 may control condenser fan motor 115 a without the need for anexternal and/or additional control system.

Referring now to FIG. 5, one embodiment of a method of internal controlof condenser fan motor assembly 115 is described in detail. At step 400,compressor 112 is turned ON by thermostat 130. At step 402, the internalcontrol system of condenser fan motor assembly 115 senses thatcompressor 112 has turned ON and turns condenser fan motor 115 a ON suchthat condenser fan motor 115 a and fan blade(s) 115 b run in a REVERSEDIRECTION. This is known as a Reverse-on-Start (ROS) function. The ROSfunction of condenser fan motor assembly 115 provides advantages overthe prior art in that it may assist in keeping condenser 114 clean byblowing accumulated dirt and debris off of the coil (not shown) ofcondenser 114 during the first mode of operation. A dirty condenser coilcan double the energy consumption of refrigeration system 110 in only afew months. A dirty condenser coil can also cause premature compressor112 failures due to overheating. The internal control system ofcondenser fan motor assembly 115 continues to run condenser fan motor115 a and fan blade(s) 115 b in the REVERSE DIRECTION until a first timeinterval has elapsed as indicated at step 404.

Accordingly, the internal control system of condenser fan motor assembly115 may include a timer for measuring elapsed time. The timer may bereset each time compressor 112 turns ON. In certain embodiments, theinternal control system of condenser fan motor assembly 115 may includea processor which may provide a timing function. The timer may beimplemented via hardware, software, and/or firmware within the internalcontrol system of condenser fan motor assembly 115 in any manner knownin the art without departing from the scope of the invention. In variousembodiments, the first time interval can be from about 5 seconds toabout 60 seconds (e.g., about 5 seconds, about 10 seconds, about 15seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55seconds, about 60 seconds). In certain embodiments, for example, firsttime interval can be from about 20 seconds to about 35 seconds. In otherembodiments, first time interval can be about 30 seconds.

After the first time interval has elapsed, at step 406, the internalcontrol system of condenser fan motor assembly 115 turns condenser fanmotor 115 a ON such that condenser fan motor 115 a and fan blade(s) 115b run in a FORWARD DIRECTION. Accordingly, at this step, condenser fanmotor 115 a and fan blade(s) 115 b turn in the “normal direction” whilecompressor 112 remains ON. At step 408, compressor 112 is turned OFF bythermostat 130. At step 410, the internal control system of condenserfan motor assembly 115 senses that compressor 112 has turned OFF andturns condenser fan motor 115 a OFF. Condenser fan motor 115 a thenremains OFF until thermostat 130 turns compressor 112 back ON.

In certain embodiments, there may be a pause between condenser fan motor115 a and fan blade(s) 115 b running in the REVERSE DIRECTION andcondenser fan motor 115 a and fan blade(s) 115 b running in the FORWARDDIRECTION. This pause may allow condenser fan motor 115 a and/or fanblade(s) 115 b of condenser fan motor assembly 115 to stop rotating. Insome embodiments, for example, the pause may be from about 1 second toabout 15 seconds (e.g., about 1 second, about 2 seconds, about 3seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8seconds, about 9 seconds, about 10 seconds, about 11 seconds, about 12seconds, about 13 seconds, about 14 seconds, about 15 seconds).

Operation of Evaporator Fan and Condenser Fan Motor Assemblies

In certain embodiments, refrigeration system 110 of refrigerator unit 10may include both an evaporator fan motor assembly 127 and a condenserfan motor assembly 115 wherein each may include a fan motor 127 a, 115a, fan blade(s) 127 b, 115 b and an independent internal control system(not shown) adapted to control the operation of evaporator fan motor 127a and condenser fan motor 115 a, respectively. As described above, theinternal control systems of each of evaporator fan motor assembly 127and condenser fan motor assembly 115 may be adapted to sense thecompressor line voltage, such that the internal control systems may beable to independently sense the compressor 112 ON or OFF state.Accordingly, the internal control systems of each of evaporator fanmotor assembly 127 and condenser fan motor assembly 115 may controlevaporator fan motor 127 a and condenser fan motor 115 a, respectively,without the need for an external and/or additional control system.

Referring now to FIG. 6, one embodiment of a method of internal controlof evaporator fan motor assembly 127 and condenser fan motor assembly115 is described in detail. At step 500, compressor 112 is turned ON bythermostat 130. At step 502, the internal control system of evaporatorfan motor assembly 127 senses that compressor 112 has turned ON andturns evaporator fan motor 127 a ON causing fan blade(s) 127 b to rotateand blow air across evaporator 120. Simultaneously or shortly after step502, at step 504, the internal control system of condenser fan motorassembly 115 senses that compressor 112 has turned ON and turnscondenser fan motor 115 a ON such that condenser fan motor 115 a and fanblade(s) 115 b run in a REVERSE DIRECTION. The internal control systemof condenser fan motor assembly 115 continues to run condenser fan motor115 a and fan blade(s) 115 b in the REVERSE DIRECTION until a first timeinterval has elapsed as indicated at step 506. Accordingly, the internalcontrol system of condenser fan motor assembly 115 may include a timerfor measuring elapsed time. The timer may be reset each time compressor112 turns ON. In certain embodiments, the internal control system ofcondenser fan motor assembly 115 may include a processor which mayprovide a timing function. The timer may be implemented via hardware,software, and/or firmware within the internal control system ofcondenser fan motor assembly 115 in any manner known in the art withoutdeparting from the scope of the invention.

After the first time interval has elapsed, at step 508, the internalcontrol system of condenser fan motor assembly 115 turns ON condenserfan motor 115 a such that condenser fan motor 115 a and fan blade(s) 115b run in a FORWARD DIRECTION. Accordingly, at this step, condenser fanmotor 115 a and fan blade(s) 115 b turn in the “normal direction” whilecompressor 112 remains ON. At step 510, compressor 112 is turned OFF bythermostat 130. At step 512, the internal control system of condenserfan motor assembly 115 senses that compressor 112 has turned OFF andturns OFF condenser fan motor 115 a. Condenser fan motor 115 a thenremains OFF until thermostat 130 turns compressor 112 back ON.

In certain embodiments, there may be a pause between condenser fan motor115 a and fan blade(s) 115 b running in the REVERSE DIRECTION andcondenser fan motor 115 a and fan blade(s) 115 b running in the FORWARDDIRECTION. This pause may allow condenser fan motor 115 a and/or fanblade(s) 115 b of condenser fan motor assembly 115 to stop rotating. Insome embodiments, for example, the pause may be from about 1 second toabout 15 seconds (e.g., about 1 second, about 2 seconds, about 3seconds, about 5 seconds, about 6 seconds, about 7 seconds, about 8seconds, about 9 seconds, about 10 seconds, about 11 seconds, about 12seconds, about 13 seconds, about 14 seconds, about 15 seconds).

In certain embodiments, during optional steps 514, 516 and 518, whilecompressor 112 remains OFF and for a second time interval aftercompressor 112 has turned OFF, evaporator fan motor 127 a remains ON. Bycontinuing to operate evaporator fan motor 127 a for a period of timeafter compressor 112 turns OFF, cooling of storage compartment 24 maycontinue because residual cool refrigerant remains in evaporator 120even after compressor 112 stops running. Accordingly, the internalcontrol system of condenser fan motor assembly 127 may include a timerfor measuring elapsed time. The timer may be reset each time compressor112 turns ON. In certain embodiments, the internal control system ofevaporator fan motor assembly 127 may include a processor which mayprovide a timing function. The timer may be implemented via hardware,software, and/or firmware within the internal control system ofevaporator fan motor assembly 127 in any manner known in the art withoutdeparting from the scope of the invention. When the second time intervalhas elapsed, the internal control system of evaporator fan motorassembly 127 turns OFF evaporator fan motor 127 a at step 520. Incertain embodiments where optional steps 514, 516 and 518 are notperformed, when compressor 112 is turned OFF at step 512, internalcontrol system of evaporator fan motor assembly 127 turns OFF evaporatorfan motor 127 a at step 520. Accordingly, in certain embodiments,evaporator fan motor 127 a may not remain ON for a second time interval.

Then at step 522, the internal control system of evaporator fan motorassembly 127 monitors whether compressor 112 has turned ON. As long ascompressor 112 remains OFF, evaporator fan motor 127 a may repeatedlycycle ON and OFF thereby taking advantage of the energy savings byturning OFF evaporator fan motor 127 a for a period of time. However,the temperature in storage compartment 24 may be maintained by turningevaporator fan motor 127 a ON for a period of time. Therefore, whilecompressor 112 is OFF, the internal control system of evaporator fanmotor assembly 127 keeps evaporator fan motor 127 a OFF during a thirdtime interval at step 524. When the third time interval has elapsed, theinternal control system of evaporator fan motor assembly 127 turns ONevaporator fan motor 127 a at step 526 causing fan blade(s) 127 b torotate and blow air across evaporator 120. Then at step 528, theinternal control system of evaporator fan motor assembly 127 monitorswhether compressor 112 has turned ON. As long as compressor 112 remainsOFF, the internal control system of evaporator fan motor assembly 127keeps evaporator fan motor 127 a ON during a fourth time interval atstep 532.

When the fourth time interval has elapsed, at step 530, the internalcontrol system of evaporator fan motor assembly 127 turns OFF evaporatorfan motor 127 a and the process returns to step 520. This process maythen repeat wherein the internal control system of the evaporator fanmotor assembly 127 intermittently cycles evaporator fan motor 127 a ONand OFF while compressor 112 is OFF. By running evaporator fan motor 127a during repeated fourth time intervals, air will still be circulatedacross evaporator 120 to maintain the temperature in storage compartment24. Additionally, by keeping evaporator fan motor 127 a OFF duringrepeated third time intervals, the heat generated by evaporator fanmotor assembly 127 may be reduced, thereby reducing heat transfer fromevaporator fan motor assembly 127 into storage compartment 24. Incertain embodiments, the amount of air required to maintain a uniformtemperature in storage compartment 24 during the compressor 112 OFFstate may be reduced by as much as a factor of 10 as compared to thecompressor 112 ON state.

As shown at steps 514 (optional step), 522, and 528, if compressor 112turns ON at any point, the cycle will be restarted at step 502 andevaporator fan motor 127 a will be turned ON or will remain ON.Accordingly, the compressor 112 ON state may interrupt the intermittentoperation of evaporator fan motor assembly 127 at any time.

The first, second, third and fourth intervals of time as described inconnection with steps 506, 516 (optional step), 524, and 530 may be anylength of time and may vary according to a variety of design and/oroperating parameters including, but not limited to, storage compartment24 volume, ambient temperatures, storage compartment 24 operatingtemperature, etc. In various embodiments, the first time interval, asdescribed at step 506, can be from about 5 seconds to about 60 seconds(e.g., about 5 seconds, about 10 seconds, about 15 seconds, about 20seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60seconds). In certain embodiments, for example, first time interval canbe from about 20 seconds to about 35 seconds. In other embodiments,first time interval can be about 30 seconds. In certain embodiments, forexample, the second interval of time, as described at step 516, may beabout zero seconds to about 1 minute (e.g., about zero seconds, about 5seconds, about 10 seconds, about 15 seconds, about 20 seconds, about 25seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45seconds, about 50 seconds, about 55 seconds, about 60 seconds). Incertain embodiments, for example, the third interval of time, asdescribed at step 524, may be about 1 minute to about 7 minutes (e.g.,about 1 minute, about 2 minutes, about 3 minutes, about 4 minutes, about5 minutes, about 6 minutes, about 7 minutes). In certain embodiments,for example, the fourth interval of time, as described at step 530, maybe about 15 seconds to about 2 minutes (e.g., about 15 seconds, about 30seconds, about 45 seconds, about 60 seconds, about 1 minute and 15seconds, about 1 minute and 30 seconds, about 1 minute and 45 seconds,about 2 minutes).

This process is alternatively described in FIG. 7 which illustrates atime plot of the operating states of compressor 112, condenser fan motorassembly 115 and evaporator fan motor assembly 127. While compressor 112is OFF, condenser fan motor 115 a and evaporator fan motor 127 a areOFF. Compressor 112 is then turned ON by thermostat 130 and the timersof the internal control systems of condenser fan motor assembly 115 andevaporator fan motor assembly 127 are reset to an initial time t₀. Attime t₀, the internal control system of condenser fan motor assembly 115turns condenser fan motor 115 a ON in a REVERSE DIRECTION and theinternal control system of evaporator fan motor assembly 127 turnsevaporator fan motor 127 a ON. At time t₁, after a first time intervalhas elapsed (t₀ to t₁), the internal control system of condenser fanmotor assembly 115 turns condenser fan motor 115 a ON in a FORWARDDIRECTION. Then at time t₂, compressor 112 is turned OFF by thermostat130 and the internal control system of condenser fan motor assembly 115senses that compressor 112 has turned OFF and turns condenser fan motor115 a OFF.

Also at time t₂, internal control system of evaporator fan motorassembly 127 senses that compressor 112 has turned OFF and mayoptionally keep evaporator fan motor 127 a running for a second timeinterval from t₂ to t₃. At time t₃, after the second time interval haselapsed, the internal control system of evaporator fan motor assembly127 turns evaporator fan motor 127 a OFF. In certain embodiments at timet₂, if internal control system of evaporator fan motor assembly 127senses that compressor 112 has turned OFF the internal control system ofevaporator fan motor assembly 127 turns evaporator fan motor 127 a OFFat time t₂. Accordingly, in certain embodiments, evaporator fan motor127 a may be OFF from t₂ to t₃ (see FIG. 7A).

Then during a third time interval from t₃ to t₄, evaporator fan motor127 a remains OFF. At time t₄, the internal control system of evaporatorfan motor assembly 127 turns evaporator fan motor 127 a ON andevaporator fan motor 127 a remains ON until a fourth time interval haselapsed (from t₄ to t₅). The internal control system of evaporator fanmotor assembly 127 then cycles evaporator fan motor 127 a ON and OFFduring successive third (from t₅ to t₆) and fourth (from t₆ to t₇) timeintervals until compressor 112 turns back ON wherein the processrestarts and the time is reset to t₀. Although only two successive thirdand fourth time intervals are illustrated in FIGS. 7 and 7A, it will beunderstood by one skilled in the art that any number of third and fourthtime intervals may occur where evaporator fan motor assemblyintermittently operates between the compressor being ON withoutdeparting from the scope of the invention.

While various steps are described herein in one order, it will beunderstood that other embodiments of the method can be carried out inany order and/or without all of the described steps without departingfrom the scope of the invention.

Thus, there has been shown and described novel methods and apparatusesof a refrigerator unit that comprises a refrigeration system with anevaporator fan motor assembly having an internal control system and/or acondenser fan motor assembly having an internal control system whereinthe evaporator fan motor and/or the condenser fan motor can be operatedintermittently, which overcome many of the problems of the prior art setforth above. It will be apparent, however, to those familiar in the art,that many changes, variations, modifications, and other uses andapplications for the subject devices and methods are possible. All suchchanges, variations, modifications, and other uses and applications thatdo not depart from the spirit and scope of the invention are deemed tobe covered by the invention which is limited only by the claims whichfollow.

1. A refrigeration system for use in a refrigerator unit, therefrigeration system comprising: (i) a compressor having an ON state andan OFF state; (ii) a condenser; (iii) a thermostat; (iv) an evaporator;and (v) an evaporator fan motor assembly comprising an evaporator fanmotor, a fan blade, and an internal control system, wherein the internalcontrol system is adapted to sense the compressor state and is furtheradapted to operate the evaporator fan motor in response to the sensedcompressor state.
 2. The refrigeration system of claim 1 wherein therefrigerator unit is a merchandiser.
 3. The refrigeration system ofclaim 1 wherein the thermostat comprises a mechanical thermostat.
 4. Therefrigeration system of claim 3 wherein the mechanical thermostatcomprises a capillary tube and a relay.
 5. The refrigeration system ofclaim 1, wherein the internal control system of the evaporator fan motorassembly is adapted to repeatedly cycle the evaporator fan motor betweenan ON state and an OFF state when the compressor is in the OFF state. 6.The refrigeration system of claim 5, wherein the evaporator fan motor isadapted to be in the OFF state for a third time interval and theevaporator fan motor is adapted to be in the ON state for a fourth timeinterval.
 7. The refrigeration system of claim 1, further comprising acondenser fan motor assembly comprising a condenser fan motor, a fanblade, and an internal control system, wherein the internal controlsystem is adapted to sense the compressor state and is further adaptedto operate the condenser fan motor in response to the sensed compressorstate.
 8. The refrigeration system of claim 7, wherein the internalcontrol system of the condenser fan motor assembly is adapted to operatethe condenser fan motor in a reverse direction during a first timeinterval after the compressor has turned to the ON state, and is adaptedto operate the condenser fan motor in a forward direction after thefirst time interval.
 9. A method of operating a refrigeration system foruse in a refrigerator unit, wherein the refrigeration system comprises acompressor having an ON state and an OFF state, a condenser, athermostat, an evaporator, and an evaporator fan motor assemblycomprising an evaporator fan motor, a fan blade, and an internal controlsystem, wherein the internal control system is adapted to repeatedlycycle the evaporator fan motor between an ON state and an OFF state whenthe compressor is in the OFF state, the method comprising the steps of:turning the compressor to the ON state; sensing by the internal controlsystem of the evaporator fan motor assembly that the compressor is inthe ON state and turning the evaporator fan motor to the ON state;turning the compressor to the OFF state; sensing by the internal controlsystem of the evaporator fan motor assembly that the compressor is inthe OFF state and repeatedly cycling the evaporator fan motor betweenthe ON state and the OFF state.
 10. The method of claim 9 wherein therefrigerator unit is a merchandiser.
 11. The method of claim 9 whereinthe thermostat comprises a mechanical thermostat.
 12. The method ofclaim 11 wherein the mechanical thermostat comprises a capillary tubeand a relay.
 13. The method of claim 9, wherein the evaporator fan motoris in the OFF state for a third time interval and the evaporator fanmotor is in the ON state for a fourth time interval.
 14. The method ofclaim 9 wherein the refrigeration system further comprises a condenserfan motor assembly comprising a condenser fan motor, a fan blade, and aninternal control system, wherein the internal control system is adaptedto operate the condenser fan motor in response to the sensed compressorstate and the method further comprises the steps of: sensing by theinternal control system of the condenser fan motor assembly that thecompressor is in the ON state and during a first time interval after thecompressor has turned to the ON state, operating the condenser fan motorin a reverse direction; after the first time interval and while thecompressor is in the ON state, operating the condenser fan motor in aforward direction; sensing by the internal control system of thecondenser fan motor assembly that the compressor is in the OFF state andturning the condenser fan motor to an OFF state.